Thermoplastic marking compositions

ABSTRACT

The subject invention pertains to thermoplastic marking compositions comprising a binder, which in turn comprise at least one homogeneous polymer. Accordingly, the subject invention provides a thermoplastic marking composition comprising: (a) from 10 to 80 weight percent of a binder, which in turn comprises: (i) from 1 to 99 weight percent of at least one homogeneous polymer; (ii) from 5 to 70 weight percent of at least one tackifier; (iii) from 0 to 10 weight percent of a polyethylene which has pendant acid functionality moieties of a non-functionalized wax; and (iv) from 0 to 20 weight percent of a plasticizer; and (b) from 20 to 90 weight percent of an inorganic filler. The subject formulations are usefully applied via spray, screed, and extrusion techniques.

This application is a 371 of PCT/US98/22123 filed Oct. 19, 1998 andclaims benefit of Provisional 60/063129 filed Oct. 21, 1997 and also60/071685 filed Jan. 16, 1998.

The subject invention pertains to thermoplastic marking compositions. Inparticular, the subject invention pertains to thermoplastic markingcompositions comprising a binder, which in turn comprise at least onehomogeneous polymer.

Thermoplastic marking formulations which comprise inorganic fillersbound by a polymeric binder are known in the art.

PCT Publication WO9623845 discloses a thermoplastic adhesive compositionsuitable for use as a road-marking, which comprises a silane-modifiedpetroleum resin containing 0.05 to 1.0 weight percent silanefunctionality, extender oil and/or plasticizer, pigment and filler. Theadhesive composition is said to provide improved adhesion of glass beadsto road surfaces for improved endurance.

Dutch Patent Publication NL7907550 discloses reflective road markingswhich are laid by applying a standard hot melt road marking compositionto the road surface, then applying a reflector containing athermoplastic to the still hot marking composition. The reflectormaterial preferably contains glass pearls, prismatic or lens reflectors,and is based on essentially the same materials as the road markingcomposition.

British Patent Publication GB2059430 discloses a hot melt thermoplasticroad marking composition comprising 7 to 38 weight percent syntheticresin, 1 to 10 weight percent plasticizer, 0 to 10 weight percentelastomer, 1 to 15 weight percent pigments, 0 to 35 weight percent glassbeads, 10 to 50 weight percent mineral aggregate, 10 to 50 weightpercent extender and 0 to 5 weight percent stabilizer. The publicationreports that the composition can easily be applied to roads by a screedor extrusion type applicator at 180 to 200° C. and has high durability,even when applied only 1.5 mm thick. The publication further providesthat glass beads at 280 to 500 grams/square meter can be applied to themolten surface.

Japanese Patent Publication JP52058737 discloses compositions which areprepared by mixing (a) 2 to 20 parts by weight ethylene-vinyl acetatecopolymer or atactic polypropylene; (b) 60 to 96 parts by weightcarboxy-modified hydrocarbon resin (with an acid value of 0.1 to 25) orester-modified hydrocarbon resin obtained by reacting thecarboxy-modified resin with alcohol; (c) 2 to 20 parts by weight lowmolecular weight polyethylene, which is optionally carboxy-modified; and(d) 200 to 700 parts by weight mineral fillers or pigment, optionallywith plasticizers or glass beads. The disclosed coatings are said tohave improved flexibility, and strength, and are obtained fromcompositions improved fluidity.

British Patent Publication GB1324553 discloses a road markingcomposition of a hot-applied, thermoplastic superimposed typecomprising: (a) aggregate,(for example, crushed marble, dolomite,calcite spar or silica sand), (b) pigment and extender, and (c) a binderconsisting of (i) 55 to 90 weight percent of polymeric unsaturatedresin, (ii) 10 to 45 weight percent of a hydrocarbon oil plasticizer,which has a flash point (open) of greater than or equal to 400 degreesF. (204° C.) and a viscosity of 6 to 10 poise at 25 degrees C., and(iii) 0 to 10 weight percent of an aliphatic monocarboxylic acid havingat least fourteen carbons, such as stearic acid or oleic acid. Thepublication discloses the inclusion of Ballotini (glass beads) formaking reflective line markings. The publication discloses the use ofTiO₂ as the pigment with whiting as the extender, or a heat stableyellow pigment, instead of TiO₂.

European Patent Publication EP 115,434 describes a hot melt adhesivecomposition comprising a copolymer of ethylene and at least onealpha-olefin having from 3 to 10 carbon atoms and a tackifier. Thecopolymer has a molecular weight of 1000 to 40,000. The alpha-olefin ispresent in an amount of from 2 to 40 percent by weight. The copolymersof the examples are prepared using a soluble vanadium catalyst. Thepublication discloses the use of the adhesives in road markingapplications.

Those in industry would find great advantage in a thermoplastic markingformulation which exhibits a consistent and low viscosity (as evidencedby a melt viscosity at 350° F. (177° C.) of no more than 5000centipoise), which exhibits reduced fuming and smoking, and whichexhibits good low temperature flexibility (as evidenced by anembrittlement temperature of −10 to −20° C.).

Accordingly, the subject invention provides a thermoplastic markingcomposition comprising:

(a) from 10 to 80 weight percent of a binder, which in turn comprises:

(i) from 1 to 99 weight percent of at least one homogeneous polymer;

(ii) from 5 to 70 weight percent of at least one tackifier;

(iii) from 0 to 10 weight percent of a polyethylene which has pendantacid functionality moieties or of a non-functionalized wax; and

(iv) from 0 to 20 weight percent of a plasticizer; and

(b) from 20 to 90 weight percent of an inorganic filler.

The subject formulations are usefully applied via spray, screed, andextrusion techniques. The subject formulations exhibit improved lowtemperature flexibility and low temperature adhesion and abrasion, andexhibit improved smoke and low odor properties at high temperatures. Thesubject formulations exhibit a broad potential range of applicationtemperatures, particularly at temperatures of from 150° C. to 250° C.,which makes them suitable for application by different means. Forinstance, the ability of the compositions to be applied at lowerapplication temperatures, that is, temperatures of 150 to 170° C., makesthem suitable for application by extrusion coating techniques; while theability of the compositions to be applied at higher applicationtemperatures, that is, temperatures of 200° C. to 250° C. makes themsuitable for application by spray coating techniques. The subjectformulations are preferably resistant to dirt pick-up, and furtherpreferably exhibit less viscosity variability relative to systems whichlack the homogeneous ethylene polymer.

The unique balance of properties characteristic of the formulations ofthe invention makes them suitable in a variety of coating, marking, andpainting applications, including but not limited to road markings,traffic signs, runway markings, pedestrian crosswalks, buildingadvertisements and markings, bicycle lanes, tennis courts, marking oftartan substitutes, stop lines, and driving course markings.

These and other embodiments are described in the following detaileddescription.

Test Methods Utilized for Characterizing the Homogeneous EthylenePolymer

Density is measured in accordance with ASTM D-792. The samples areannealed at ambient conditions for 24 hours before the measurement istaken.

Melt index (I₂), is measured in accordance with ASTM D-1238, condition190° C./2.16 kg (formally known as “Condition (E)”).

Molecular weight is determined using gel permeation chromatography (GPC)on a Waters 150° C. high temperature chromatographic unit equipped withthree mixed porosity columns (Polymer Laboratories 103, 104, 105, and106), operating at a system temperature of 140° C. The solvent is1,2,4-trichlorobenzene, from which 0.3 percent by weight solutions ofthe samples are prepared for injection. The flow rate is 1.0 mL/minuteand the injection size is 100 microliters.

The molecular weight determination is deduced by using narrow molecularweight distribution polystyrene standards (from Polymer Laboratories) inconjunction with their elution volumes. The equivalent polyethylenemolecular weights are determined by using appropriate Mark-Houwinkcoefficients for polyethylene and polystyrene (as described by Williamsand Word in Journal of Polymer Science, Polymer Letters, Vol. 6, (621)1968) to derive the following equation:

M _(polyethylene) =a*(M _(polystyrene))b.

In this equation, a=0.4316 and b=1.0. Weight average molecular weight,M_(w), is calculated in the usual manner according to the followingformula: M_(w)=Σw_(i)*M_(i), where w_(i) and M_(i) are the weightfraction and molecular weight, respectively, of the ith fraction elutingfrom the GPC column.

Melt viscosity of polymer components is determined in accordance withthe following procedure using a Brookfield Laboratories DVII+ Viscometerin disposable aluminum sample chambers. The spindle used is a SC-31hot-melt spindle, suitable for measuring viscosities in the range offrom 10 to 100,000 centipoise (0.1 to 1000 grams/(cm·second)). A cuttingblade is employed to cut samples into pieces small enough to fit intothe 1 inch wide, 5 inches long (2.5 cm wide, 13 cm long) sample chamber.The sample is placed in the chamber, which is in turn inserted into aBrookfield Thermosel and locked into place with bent needle-nose pliers.The sample chamber has a notch on the bottom that fits the bottom of theBrookfield Thermosel to ensure that the chamber is not allowed to turnwhen the spindle is inserted and spinning. The sample is heated to 350°F. (177° C.), with additional sample being added until the melted sampleis about 1 inch (2.5 cm) below the top of the sample chamber. Theviscometer apparatus is lowered and the spindle submerged into thesample chamber. Lowering is continued until brackets on the viscometeralign on the Thermosel. The viscometer is turned on, and set to a shearrate which leads to a torque reading in the range of 30 to 60 percent.Readings are taken every minute for about 15 minutes, or until thevalues stabilize, which final reading is recorded.

The adhesives of the invention comprise at least one homogeneousethylene/α-olefin interpolymer which is an interpolymer of ethylene andat least one C₃-C₂₀ α-olefin. The term “interpolymer” is used herein toindicate a copolymer, or a terpolymer, or a higher order polymer. Thatis, at least one other comonomer is polymerized with ethylene to makethe interpolymer.

By the term “homogenous”, it is meant that any comonomer is randomlydistributed within a given interpolymer molecule and substantially allof the interpolymer molecules have the same ethylene/comonomer ratiowithin that interpolymer. The melting peak of homogeneous linear andsubstantially linear ethylene polymers, as obtained using differentialscanning calorimetry, will broaden as the density decreases and/or asthe number average molecular weight decreases. However, unlikeheterogeneous polymers, when a homogeneous polymer has a melting peakgreater than 115° C. (such as is the case of polymers having a densitygreater than 0.940 g/cm³), it does not additionally have a distinctlower temperature melting peak.

The homogeneous ethylene/α-olefin interpolymers useful in the inventionare characterized as having a narrow molecular weight distribution(M_(w)/M_(n)). For the homogeneous ethylene/α-olefins useful in thepractice of the invention, the M_(w)/M_(n) is from 1.5 to 2.5,preferably from 1.8 to 2.2, most preferably about 2.0.

Homogeneously branched linear ethylene/α-olefin interpolymers may beprepared using polymerization processes (for example, as described byElston in U.S. Pat. No. 3,645,992) which provide a homogeneous shortchain branching distribution. In his polymerization process, Elston usessoluble vanadium catalyst systems to make such polymers. However, otherssuch as Mitsui Petrochemical Company and Exxon Chemical Company haveused so-called single site catalyst systems to make polymers having ahomogeneous linear structure. U.S. Pat. No. 4,937,299 to Ewen et al. andU.S. Pat. No. 5,218,071, to Tsutsui et al. disclose the use of catalystsystems based on hafnium for the preparation of homogeneous linearethylene polymers. Homogeneous linear ethylene/α-olefin interpolymersare currently available from Mitsui Petrochemical Company under thetrade name “Tafmer” and from Exxon Chemical Company under the trade name“Exact”.

Substantially linear ethylene/α-olefin interpolymers are available fromThe Dow Chemical Company as Affinity™ polyolefin plastomers.Substantially linear ethylene/α-olefin interpolymers may be prepared inaccordance with the techniques described in U.S. Pat. No. 5,272,236,U.S. Pat. No. 5,278,272, and U.S. Pat. No. 5,665,800.

Especially preferred homogeneous ethylene/α-olefin polymers areultra-low molecular weight polymers may be made in accordance with theteaching of PCT Publication WO 97/26287, which is equivalent to U.S.patent application Ser. No. 08/784,683, filed on Jan. 22, 1997.

The at least one homogeneous polymer will be an interpolymer of ethylenewith at least one comonomer selected from the group consisting of C₃-C₂₀α-olefins, non-conjugated dienes, and cycloalkenes. Exemplary C₃-C₂₀α-olefins include propylene, isobutylene, 1-butene, 1-hexene,4-methyl-1-pentene, 1-heptene, and 1-octene. Preferred C₃-C₂₀ α-olefinsinclude C₄-C₂₀ α-olefins, such as 1-butene, 1-hexene,4-methyl-1-pentene, 1-heptene, and 1-octene, more preferably 1-hexeneand 1-octene. Exemplary cycloalkenes include cyclopentene, cyclohexene,and cyclooctene. The non-conjugated dienes suitable as comonomers,particularly in the making of ethylene/α-olefin/diene terpolymers, aretypically non-conjugated dienes having from 6 to 15 carbon atoms.Representative examples of suitable non-conjugated dienes include:

(a) Straight chain acyclic dienes such as 1,4-hexadiene; 1,5-heptadiene;and 1,6-octadiene;

(b) Branched chain acyclic dienes such as 5-methyl-1,4-hexadiene;3,7-dimethyl-1,6-octadiene; and 3,7-dimethyl-1,7-octadiene;

(c) Single ring alicyclic dienes such as 4-vinylcyclohexene;1-allyl-4-isopropylidene cyclohexane; 3-allyicyclopentene;4-allylcyclohexene; and 1-isopropenyl-4-butenylcyclohexene;

(d) Multi-ring alicyclic fused and bridged ring dienes such asdicyclopentadiene; alkenyl, alkylidene, cycloalkenyl, andcycloalkylidene norbornenes, such as 5-methylene-2-norbornene;5-methylene-6-methyl-2-norbornene;5-methylene-6,6-dimethyl-2-norbornene; 5-propenyl-2-norbornene;5-(3-cyclopentenyl)-2-norbornene; 5-ethylidene-2-norbornene; and5-cyclohexylidene-2-norbornene.

One preferred conjugated diene is piperylene. The preferred dienes areselected from the group consisting of 1,4-hexadiene; dicyclopentadiene;5-ethylidene-2-norbornene; 5-methylene-2-norbornene; 7-methyl-1,6octadiene; piperylene; and 4-vinylcyclohexene.

The molecular weight of the ethylene/α-olefin interpolymer will beselected on the basis of the desired performance attributes of thethermoplastic marking formulation. It is well known that the molecularweight of the polymer will correlate with the melt viscosity of thepolymer. Typically, the ethylene/α-olefin interpolymer will have a meltviscosity at 350° F. (177° C.) of at least 500 centipoise, preferably atleast 1500 centipoise (15 grams/cm·second), more preferably at least2500 centipoise (25 grams/cm·second, and most preferably at least 3000centipoise (30 grams/cm·second). Likewise, the ethylene/α-olefininterpolymer will typically have a melt viscosity at 350° F. (177° C.)of no more than 14,000 centipoise (140 grams/cm·second), preferably nomore than 9000 centipoise (90 grams/cm·second), more preferably no morethan 7500 centipoise (75 grams/cm·second), and most preferably no morethan 5000 centipoise (50 grams/cm·second).

When the ethylene/α-olefin interpolymer has an ultra-low molecularweight, a number average molecular weight less than 11,000, theethylene/α-olefin interpolymer leads to a low polymer and formulationviscosity but is characterized by a peak crystallization temperaturewhich is greater than that of corresponding higher molecular weightmaterials of the same density. In pressure sensitive adhesiveapplications, the increase in peak crystallization temperaturetranslates to an increased heat resistance. Ultra-low molecular weightethylene/α-olefin interpolymers are more fully described below.

The density of the ethylene/α-olefin interpolymer will likewise beselected on the basis of the desired performance attributes of theadhesive formulation. Typically, however, the ethylene/α-olefininterpolymer will have a density of at least 0.855 g/cm³, preferably atleast 0.860 g/cm³, and more preferably at least 0.870 g/cm³. Typically,the ethylene/α-olefin interpolymer will have a density of no more than0.965 g/cm³, preferably no more than 0.920 g/cm³, more preferably nomore than 0.890 g/cm³, and even more preferably no more than 0.880g/cm³, and most preferably no more than 0.875 g/cm³.

The ethylene/α-olefin interpolymer will be present in the bindercomponent of the thermoplastic marking composition of the invention inan amount greater than 1, preferably greater than 5, and more preferablygreater than 10 weight percent. The ethylene/α-olefin interpolymer willtypically be present in the binder component of the thermoplasticmarking composition of the invention in an amount of not more than 99,preferably not more than 90, and more preferably not more than 80 weightpercent. In especially preferred embodiments, the ethylene/α-olefininterpolymer will be present in the binder component in an amount offrom 25 to 50 weight percent.

The first polymer may be suitably prepared using a single sitemetallocene or a constrained geometry metal complex. Constrainedgeometry catalysts are disclosed in U.S. application Ser. No. 545,403,filed Jul. 3, 1990 (EP-A-416,815); U.S. application Ser. No. 702,475,filed May 20, 1991 (EP-A-514,828); as well as U.S. Pat Nos. 5,470,993,5,374,696, 5,231,106, 5,055,438, 5,057,475, 5,096,867, 5,064,802, and5,132,380. In U.S. Ser. No. 720,041, filed Jun. 24, 1991, (EP-A-514,828)certain borane derivatives of the foregoing constrained geometrycatalysts are disclosed and a method for their preparation taught andclaimed. In U.S. Pat. No. 5,453,410 combinations of cationic constrainedgeometry catalysts with an alumoxane were disclosed as suitable olefinpolymerization catalysts.

Suitable activating cocatalysts and activating techniques have beenpreviously taught with respect to different metal complexes in thefollowing references: EP-A-277,003, U.S. Pat. No. 5,153,157, U.S. Pat.No. 5,064,802, EP-A-468,651 (equivalent to U.S. Ser. No. 07/547,718),EP-A-520,732 (equivalent to U.S. Ser. No. 07/876,268), WO 95/00683(equivalent to U.S. Ser. No. 08/82,201), and EP-A-520,732 (equivalent toU.S. Ser. No. 07/884,966) filed May 1, 1992.

Catalysts found to be particularly suitable in the preparation ofsubstantially linear ethylene/α-olefin interpolymers include, forinstance, the catalysts described in the Examples set forth below, asactivated by trispentafluorophenylborane and triisobutylaluminummodified methylalumoxane cocatalysts.

The molar ratio of metal complex: activating cocatalyst employedpreferably ranges from 1:1000 to 2:1, more preferably from 1:5 to 1.5:1,most preferably from 1:2 to 1:1. In the preferred case in which a metalcomplex is activated by trispentafluorophenylborane andtriisobutylaluminum modified methylalumoxane, thetitanium:boron:aluminum molar ratio is typically from 1:10:50 to1:0.5:0.1, most typically from 1:3:5.

A support, especially silica, alumina, or a polymer (especiallypoly(tetrafluoroethylene) or a polyolefin) may be employed, anddesirably is employed when the catalysts are used in a gas phasepolymerization process. The support is preferably employed in an amountto provide a weight ratio of catalyst (based on metal):support from1:100,000 to 1:10, more preferably from 1:50,000 to 1:20, and mostpreferably from 1:10,000 to 1:30. In most polymerization reactions themolar ratio of catalyst:polymerizable compounds employed is from 10⁻¹²:1to 10⁻¹:1, more preferably from 10⁻⁹:1 to 10⁻⁵:1.

At all times, the individual ingredients as well as the recoveredcatalyst components must be protected from oxygen and moisture.Therefore, the catalyst components and catalysts must be prepared andrecovered in an oxygen and moisture tree atmosphere. Preferably,therefore, the reactions are performed in the presence of a dry, inertgas such as, for example, nitrogen.

The polymerization may be carried out as a batchwise or a continuouspolymerization process, with continuous polymerization processes beingrequired for the preparation of substantially linear polymers. In acontinuous process, ethylene, comonomer, and optionally solvent anddiene are continuously supplied to the reaction zone and polymer productcontinuously removed therefrom.

In general, the first polymer may be polymerized at conditions forZiegler-Natta or Kaminsky-Sinn type polymerization reactions, that is,reactor pressures ranging from atmospheric to 3500 atmospheres (350MPa). The reactor temperature should be greater than 80° C., typicallyfrom 100° C. to 250° C., and preferably from 100° C. to 150° C., withtemperatures at the higher end of the range, temperatures greater than100° C. favoring the formation of lower molecular weight polymers.

In conjunction with the reactor temperature, the hydrogen:ethylene molarratio influences the molecular weight of the polymer, with greaterhydrogen levels leading to lower molecular weight polymers. When thedesired polymer has an I₂ of 1 g/10 min, the hydrogen:ethylene molarratio will typically be 0:1. When the desired polymer has an I₂ of 1000g/10 min., the hydrogen:ethylene molar ratio will typically be from0.45:1 to 0.7:1. The upper limit of the hydrogen:ethylene molar ratio isfrom 2.2 to 2.5:1.

Generally the polymerization process is carried out with a differentialpressure of ethylene of from 10 to 1000 psi (70 to 7000 kPa), mostpreferably from 40 to 60 psi (30 to 300 kPa). The polymerization isgenerally conducted at a temperature of from 80 to 250° C., preferablyfrom 90 to 170° C., and most preferably from greater than 95° C. to 140°C.

In most polymerization reactions the molar ratio ofcatalyst:polymerizable compounds employed is from 10⁻¹²:1 to 10⁻¹:1,more preferably from 10⁻⁹:1 to 10⁻⁵:1. Solution polymerizationconditions utilize a solvent for the respective components of thereaction. Preferred solvents include mineral oils and the varioushydrocarbons which are liquid at reaction temperatures. Illustrativeexamples of useful solvents include alkanes such as pentane,iso-pentane, hexane, heptane, octane and nonane, as well as mixtures ofalkanes including kerosene and Isopar-E™, available from Exxon ChemicalsInc.; cycloalkanes such as cyclopentane and cyclohexane; and aromaticssuch as benzene, toluene, xylenes, ethylbenzene and diethylbenzene.

The solvent will be present in an amount sufficient to prevent phaseseparation in the reactor. As the solvent functions to absorb heat, lesssolvent leads to a less adiabatic reactor. The solvent:ethylene ratio(weight basis) will typically be from 2.5:1 to 12:1, beyond which pointcatalyst efficiency suffers. The most typical solvent:ethylene ratio(weight basis) is in the range of from 5:1 to 10:1.

The ethylene/α-olefin interpolymer may alternatively be prepared in agas phase polymerization process, using the catalysts as described aboveas supported in an inert support, such as silica. The ethylene/α-olefininterpolymer may further be made in a slurry polymerization process,using the catalysts as described above as supported in an inert support,such as silica. As a practical limitation, slurry polymerizations takeplace in liquid diluents in which the polymer product is substantiallyinsoluble. Preferably, the diluent for slurry polymerization is one ormore hydrocarbons with less than 5 carbon atoms. If desired, saturatedhydrocarbons such as ethane, propane or butane may be used in whole orpart as the diluent. Likewise the α-olefin monomer or a mixture ofdifferent α-olefin monomers may be used in whole or part as the diluent.Most preferably the diluent comprises in at least major part theα-olefin monomer or monomers to be polymerized.

As used herein, the term “tackifier” means any of the compositionsdescribed below which are useful to impart tack to the hot melt adhesivecomposition. ASTM D-1878-61T defines tack as “the property of a materialwhich enables it to form a bond of measurable strength immediately oncontact with another surface”.

The binder component of the thermoplastic marking composition of theinvention will comprise at least 5 weight percent tackifier, typicallyat least 10 weight percent tackifier, and more preferably at least 20weight percent tackifier. Likewise, the binder component of thethermoplastic marking composition of the invention will comprise no morethan 70 weight percent tackifier, preferably no more than 60 weightpercent tackifier, and more preferably no more than 50 weight percenttackifier.

In general terms, the tackifying resins useful in the binder componentsof the thermoplastic marking compositions of the invention compriseresins derived from renewable resources such as rosin derivativesincluding wood rosin, tall oil, gum rosin; rosin esters, natural andsynthetic terpenes, and derivatives of such. Aliphatic, aromatic ormixed aliphatic-aromatic petroleum based tackifiers are also useful inthe binder component of the thermoplastic marking compositions of thisinvention. Representative examples of useful hydrocarbon resins includesalpha-methyl styrene resins, branched and unbranched C₅ resins, C₉resins, C₁₀ resins, as well as styrenic and hydrogenated modificationsof such.

Tackifying resins range from being a liquid at 37° C. to having a ringand ball softening point of about 135° C. Solid tackifying resins with asoftening point greater than about 100° C., more preferably with asoftening point greater than about 130° C. are particularly useful toimprove the cohesive strength of the binder component of thethermoplastic marking compositions of the present invention,particularly when only a single homogeneous ethylene/α-olefininterpolymer is utilized.

For the binder component of the thermoplastic marking compositions ofthe invention, the preferred tackifying resin is predominantlyaliphatic. However, tackifying resins with increasing aromatic characterare also useful, particularly when a second tackifier or mutuallycompatible plasticizer is employed.

A plasticizer is broadly defined as a typically organic composition thatcan be added to thermoplastics, rubbers and other resins to improveextrudability, flexibility, workability, or stretchability. In preferredembodiments of the invention, the plasticizer will be provided to thebinder component of the thermoplastic marking composition in amounts upto 20 weight percent, preferably less than 15 weight percent, and morepreferably less than 10 weight percent, of the binder component of thethermoplastic marking composition. While the use of a plasticizer isoptional, when it is utilized, it will typically be provided in thebinder component in an amount of at least 1 weight percent, preferablyat least 3 weight percent.

The plasticizer may be either a liquid or a solid at ambienttemperature. Exemplary liquid plasticizers include hydrocarbon oils,polybutene, and liquid elastomers. Plasticizer oils are primarilyhydrocarbon oils which are low in aromatic content and which areparaffinic or naphthenic in character. Plasticizer oils are preferablylow in volatility, transparent and have as little color and odor aspossible. The use of plasticizers in this invention also contemplatesthe use of olefin oligomers, low molecular weight polymers, vegetableoils and their derivatives and similar plasticizing liquids.

When a solid plasticizing agent is employed, it will preferably have asoftening point above 60° C. It is believed that by combining thehomogeneous ethylene/α-olefin interpolymer with a suitable tackifyingresin and a solid plasticizer such as a cyclohexane dimethanoldibenzoate plasticizer, the resulting thermoplastic marking compositionmay be applied at temperatures below 120° C., preferably below 100° C.Although a 1,4-cyclohexane dimethanol dibenzoate compound commerciallyavailable from Velsicol under the trade name Benzoflex™ 352 isexemplified, any solid plasticizer that will subsequently recrystallizein the compounded thermoplastic composition is suitable. Otherplasticizers that may be suitable for this purpose are described in EP0422 108 B1 and EP 0 410 412 B1, both assigned to H. B. Fuller Company.

Waxes may be usefully employed in the binder component of thethermoplastic marking compositions of the present invention,particularly when the thermoplastic marking composition is intended tobe relatively tack free upon cooling and solidifying, such as forvarious packaging and bookbinding applications as well as foam in placegaskets. Waxes useful in the binder component of the thermoplasticmarking compositions of the present invention include paraffin waxes,microcrystalline waxes, Fischer-Tropsch, polyethylene and by-products ofpolyethylene wherein M_(w) is less than 3000. The wax is present in thebinder component in an amount less than 10 percent by weight, preferablyless than 8 percent by weight. While the wax is optional, when it isutilized, it will typically be provided in an amount of at least 1weight percent, preferably at least 3 weight percent.

Also suitable are ultra-low molecular weight ethylene/α-olefininterpolymers prepared using a constrained geometry catalyst, and may bereferred to as homogeneous waxes. Such homogeneous waxes, as well asprocesses for preparing such homogeneous waxes, are set forth in theExamples below. Homogeneous waxes, in contrast to paraffinic waxes andcrystalline ethylene homopolymer or interpolymer waxes, will have aM_(w)/M_(n) of from 1.5 to 2.5, preferably from 1.8 to 2.2.

Homogeneous waxes will be either ethylene homopolymers or interpolymersof ethylene and a C₃-C₂₀ α-olefin. The homogeneous wax will have anumber average molecular weight less than 6000, preferably less than5000. Such homogeneous waxes will typically have a number averagemolecular weight of at least 800, preferably at least 1300.

Homogeneous waxes lead to a low polymer and formulation viscosity, butare characterized by peak crystallization temperatures which are greaterthan the peak crystallization temperatures of corresponding highermolecular weight materials of the same density. In polymeric bindingapplications, the increase in peak crystallization temperaturetranslates to an increased heat resistance, improved creep resistance,and improved shear adhesion failure temperatures.

In addition to or in place of a non-functionalized wax, the binderformulation will optionally contain a polyethylene having pendant acidfunctionality moieties. Any unsaturated organic compound containing atleast one ethylenic unsaturation (for example, at least one doublebond), at least one carbonyl group (—C═O), and that will graft to apolyethylene can be used in the practice of this invention.Representative of compounds that contain at least one carbonyl group arethe carboxylic acids, anhydrides, esters and their salts, both metallicand nonmetallic. Preferably, the organic compound contains ethylenicunsaturation conjugated with a carbonyl group. Representative compoundsinclude maleic, fumaric, acrylic, methacrylic, itaconic, crotonic,methyl crotonic, and cinnamic acid and their anhydride, ester and saltderivatives, if any. Maleic anhydride is the preferred unsaturatedorganic compound containing at least one ethylenic unsaturation and atleast one carbonyl group.

The unsaturated organic compound content of the acid-functionalizedpolyethylene is at least 0.01 weight percent, and preferably at least0.05 weight percent, based on the combined weight of the polymer and theorganic compound. The maximum amount of unsaturated organic compoundcontent can vary to convenience, but typically it does not exceed 10weight percent, preferably it does not exceed 5 weight percent, and morepreferably it does not exceed 2 weight percent.

The unsaturated organic compound can be grafted to the polyethylene byany known technique, such as those taught in U.S. Pat. No. 3,236,917 andU.S. Pat. No. 5,194,509. For example, in the '917 patent the polymer isintroduced into a two-roll mixer and mixed at a temperature of 60° C.The unsaturated organic compound is then added along with a free radicalinitiator, such as, for example, benzoyl peroxide, and the componentsare mixed at 30° C. until the grafting is completed. In the '509 patent,the procedure is similar except that the reaction temperature is higher,for example, 210 to 300° C., and a free radical initiator is not used oris used at a reduced concentration.

An alternative and preferred method of grafting is taught in U.S. Pat.No. 4,950,541, by using a twin-screw devolatilizing extruder as themixing apparatus. The polyethylene and unsaturated organic compound aremixed and reacted within the extruder at temperatures at which thereactants are molten and in the presence of a free radical initiator.Preferably, the unsaturated organic compound is injected into a zonemaintained under pressure within the extruder.

The acid-functionalized polyethylene is present in the binder componentin an amount less than 10 percent by weight, preferably less than 8percent by weight. While the acid-functionalized polyethylene isoptional, when it is utilized, it will typically be provided in anamount of at least 1 weight percent, preferably at least 3 weightpercent.

Any polyethylene which may be acid-functionalized will be suitable inthe practice of the invention. However, one preferred class ofpolyethylene is the class of ultra-low molecular weightethylenelo/α-olefin interpolymers prepared using a constrained geometrycatalyst. Such polyethylene will have an M_(w)/M_(n) of from 1.5 to 2.5,preferably from 1.8 to 2.2.

The polyethylene, prior to acid-functionalization, will preferably havea number average molecular weight less than 6000, preferably less than5000; and will typically have a number average molecular weight of atleast 800, preferably at least 1300, as determined by gel permeationchromatography.

As is known in the art, various other components can be added to modifythe tack, color, or odor, of the thermoplastic marking composition.Additives such as antioxidants (for example, hindered phenolics (forexample, Irganox™ 1010, Irganox™ 1076), phosphites (for example,Irgafos™ 168)), antiblock additives, pigments, and fillers, can also beincluded in the formulations. It is generally preferred that theadditives should be relatively inert and have negligible effects uponthe properties contributed by the homogeneous linear or substantiallylinear interpolymer, tackifying agent, and plasticizing oil.

In addition to the binder component, the thermoplastic markingcompositions of the invention will further comprise at least oneinorganic filler. Fillers which are useful in the formulations includesand (quartz), dolomite or talc, carbon black or graphite, calciumcarbonate, flyash, cement dust, clay, feldspar, nepheline, silica orglass, fumed silica, alumina, magnesium oxide, zinc oxide, bariumsulfate, aluminum silicate, calcium silicate, titanium dioxide,titanates, glass microspheres, chalk, and pigments. Of these fillers,sand (quartz), dolomite or talc, glass microspheres, pigments, andmixtures thereof, are preferred.

The filler will be provided to the thermoplastic marking composition inan amount of from 40 to 90 weight percent, preferably from 50 to 90weight percent. In particularly preferred embodiments, the filler willcomprise a combination of the following: 0 to 60 weight percent sand, 0to 100 percent dolomite or talc, 0 to 50 weight percent glassmicrospheres, and 1 to 20 weight percent pigment.

When it is desired that the thermoplastic coating composition havereflective attributes, a reflective inorganic filler will be employed.One particularly preferred reflective inorganic filler is glassmicrospheres. When a reflective inorganic filler is employed, it willtypically be provided to the thermoplastic coating composition in anamount of at least 5 weight percent, preferably at least 10 weightpercent, and more preferably at least 20 weight percent. The reflectiveinorganic filler will be provided to the thermoplastic coatingcomposition in an amount of no more than 70, preferably no more than 50weight percent, and most preferably no more than 40 weight percent.

Certain inorganic fillers will typically be employed in an effort toreduce the cost of the formulation. One suitable extending filler isdolomite clay. When employed, the dolomite filler will be provided in anamount of at least 10 weight percent, more preferably at least 20 weightpercent, and most preferably at least 30 weight percent of thethermoplastic coating composition. The dolomite filler will typically beprovided in an amount of no more than 80 weight percent, more preferablyno more than 75 weight percent, and most preferably no more than 70weight percent of the thermoplastic coating composition.

The thermoplastic marking compositions of the invention areadvantageous, in that they may be readily designed to be applied by thevarious techniques used in the industry. For instance, the subjectinvention has permitted the development of a single formulation, whichmay be usefully applied by extrusion, screed, or spray techniques.

The thermoplastic marking compositions of the invention will preferablyexhibit an adhesion, as measured in accordance with the techniques setforth in Example Two, of at least 1.0 N/mm², preferably at least 1.2N/mm², more preferably at least 1.3 N/mm², and most preferably at least1.5 N/mm².

The thermoplastic marking compositions of the invention will preferablyexhibit a luminance factor, as measured in accordance with thetechniques set forth in Example Two, of at least 70, preferably at least75, more preferably at least 76, and most preferably at least 78.

The thermoplastic marking compositions of the invention further exhibitgood low temperature abrasion resistance. The subject formulationsexhibit improved low temperature flexibility and low temperatureadhesion, and exhibit improved smoke and low odor properties at hightemperatures. The subject formulations exhibit a broad potential rangeof application temperatures, particularly at temperatures of from 150°C. to 250° C., which makes them suitable for application by differentmeans. For instance, the ability of the compositions to be applied atlower application temperatures, that is, temperatures of about 150 to170° C., makes them suitable for application by extrusion coatingtechniques; while the ability of the compositions to be applied athigher application temperatures, that is, temperatures of 200° C. to250° C. makes them suitable for application by spray coating techniques.The subject formulations are preferably resistant to dirt pick-up, andfurther preferably exhibit less viscosity variability relative tosystems which lack the homogeneous ethylene polymer.

The subject formulations are usefully applied via spray, screed, andextrusion techniques. In addition, the subject formulations may beprovided as preformed tapes, which are laid upon the surface and bondedto it by heating with, for example, a gas flame, optionally under someapplied pressure, as by rolling.

Exemplary applications for the thermoplastic marking compositions of theinvention are in hot melt extrusion road marking; hot melt spray roadmarking; hot melt hand applied road markings; colored hot melt markedbicycle lanes applied by spray or extrusion; marking ofsimulation/training roads for icy surface driving; preformed extrudedtraffic symbols (such as arrows, letters, etc.) and tapes (such as fortraffic safety, information, decoration, etc.) (also called premarks orhot melt tapes); marking of flexible and soft sports/playgroundsurfaces, such as tartan (for instance, in the marking of tennis courts,outdoor and indoor sports floorings, etc.); safety markings on ships,oil rigs, etc.; and reflecting traffic safety coatings for tunnels,concrete, metals with glass beads or other reflecting/self-glowingpigments.

In one preferred application, the subject thermoplastic markingcompositions will be employed in embossed road markings. Embossed roadmarkings are formed by extrusion of a marking composition onto asurface; applying reflective particles, such as glass beads, to theextruded marking; and embossing the extruded marking such as to createchannels or other ridges. Such embossed markings are desirable, in thatthey provide enhanced water drainage and improve nighttime reflectiveproperties, particularly in rainy weather. The thermoplastic markingcompositions of the invention are advantageous in embossed road markingapplications, as they provide the requisite degree of flexibility,adhesion, and abrasion, even under cold temperature conditions.

The following examples are provided to illustrate typical embodiments ofthe invention, and are not intended to serve as limits as to its scope.

Preparation of Homogeneous Ethylene Polymers

The homogeneous ethylene polymers are prepared in accordance with theprocedure of PCT Publication WO 97/26287, which is equivalent to U.S.patent application Ser. No. 08/784,683, filed on Jan. 22, 1997.

The procedure for the preparation of Polymer A is set forth as follows:

The procedure for preparing the ultra-low molecular weight ethylenepolymers is as follows.

Catalyst Preparation

Part 1: Preparation of TiCl₃(DME)_(1.5)

The apparatus (referred to as R-1) was set-up in the hood and purgedwith nitrogen; it consisted of a 10 L glass kettle with flush mountedbottom valve, 5-neck head, polytetrafluoroethylene gasket, clamp, andstirrer components (bearing, shaft, and paddle). The necks were equippedas follows: stirrer components were put on the center neck, and theouter necks had a reflux condenser topped with gas inlet/outlet, aninlet for solvent, a thermocouple, and a stopper. Dry, deoxygenateddimethoxyethane (DME) was added to the flask (approx. 5 L). In thedrybox, 700 g of TiCl₃ was weighed into an equalizing powder additionfunnel; the funnel was capped, removed from the drybox, and put on thereaction kettle in place of the stopper. The TiCl₃ was added over about10 minutes with stirring. After the addition was completed, additionalDME was used to wash the rest of the TiCl₃ into the flask. The additionfunnel was replaced with a stopper, and the mixture heated to reflux.The color changed from purple to pale blue. The mixture was heated forabout 5 hours, cooled to room temperature, the solid was allowed tosettle, and the supematant was decanted from the solid. TheTiCl₃(DME)_(1.5) was left in R-1 as a pale blue solid.

Part 2: Preparation of [(Me₄C₅)SiMe₂N-t-Bu][MgCl]₂

The apparatus (referred to as R-2) was set-up as described for R-1,except that flask size was 30 L. The head was equipped with seven necks;stirrer in the center neck, and the outer necks containing condensertopped with nitrogen inlet/outlet, vacuum adapter, reagent additiontube, thermocouple, and stoppers. The flask was loaded with 4.5 L oftoluene, 1.14 kg of (Me₄C₅H)SiMe₂NH-t-Bu, and 3.46 kg of 2 M i-PrMgCl inEt₂O. The mixture was then heated, and the ether allowed to boil offinto a trap cooled to −78° C. After four hours, the temperature of themixture had reached 75° C. At the end of this time, the heater wasturned off and DME was added to the hot, stirring solution, resulting inthe formation of a white solid. The solution was allowed to cool to roomtemperature, the material was allowed to settle, and the supernatant wasdecanted from the solid. The [(Me₄C₅)SiMe₂N-t-Bu][MgCl]₂ was left in R-2as an off-white solid.

Part 3: Preparation of [(η⁵-Me₄C₅)SiMe₂N-t-Bu]TiMe₂

The materials in R-1 and R-2 were slurried in DME (3 L of DME in R-1 and5 L in R-2). The contents of R-1 were transferred to R-2 using atransfer tube connected to the bottom valve of the 10 L flask and one ofthe head openings in the 30 L flask. The remaining material in R-1 waswashed over using additional DME. The mixture darkened quickly to a deepred/brown color, and the temperature in R-2 rose from 21° C. to 32° C.After 20 minutes, 160 mL of CH₂Cl₂ was added through a dropping funnel,resulting in a color change to green/brown. This was followed by theaddition of 3.46 kg of 3 M MeMgCl in THF, which caused a temperatureincrease from 22° C. to 5° C. The mixture was stirred for 30 minutes,then 6 L of solvent was removed under vacuum. Isopar™ E hydrocarbon (6L) was added to the flask. This vacuum/solvent addition cycle wasrepeated, with 4 L of solvent removed and 5 L of Isopar™ E hydrocarbonadded. In the final vacuum step, an additional 1.2 L of solvent wasremoved. The material was allowed to settle overnight, then the liquidlayer decanted into another 30 L glass kettle (R-3). The solvent in R-3was removed under vacuum to leave a brown solid, which was re-extractedwith Isopar E; this material was transferred into a storage cylinder.Analysis indicated that the solution (17.23 L) was 0.1534 M in titanium;this is equal to 2.644 moles of [(η⁵-Me₄C₅)SiMe₂N-t-Bu]TiMe₂. Theremaining solids in R-2 were further extracted with Isopar™ Ehydrocarbon, the solution was transferred to R-3, then dried undervacuum and re-extracted with Isopar™ E hydrocarbon. This solution wastransferred to storage bottles; analysis indicated a concentration of0.1403 M titanium and a volume of 4.3 L (0.6032 moles[(η⁵-Me₄C₅)SiMe₂N-t-Bu]TiMe₂). This gives an overall yield of 3.2469moles of [(η⁵-Me₄C₅)SiMe₂N-t-Bu]TiMe₂, or 1063 g. This is a 72 percentyield overall based on the titanium added as TiCl₃.

Polymerization

Polymer A was prepared in accordance with the following procedure andutilizing the reaction conditions set forth in Table One.

The ethylene and the hydrogen were combined into one stream before beingintroduced into the diluent mixture, a mixture of C₈-C₁₀ saturatedhydrocarbons, for example, ISOPAR-E hydrocarbon mixture (available fromExxon Chemical Company) and the comonomer. The comonomer was 1-octene.The reactor feed mixture was continuously injected into the reactor.

The metal complex and cocatalysts were combined into a single stream andwere also continuously injected into the reactor. The cocatalyst wastris(pentafluorophenyl)borane, available as a 3 weight percent solutionin Isopar™-E mixed hydrocarbon, from Boulder Scientific. Aluminum wasprovided in the form of a solution of modified methylalumoxane (MMAOType 3A) in heptane, which is available at a 2 weight percent aluminumconcentration from Akzo Nobel Chemical Inc.

Sufficient residence time was allowed for the metal complex andcocatalyst to react prior to introduction into the polymerizationreactor. In each polymerization reaction, the reactor pressure was heldconstant at about 475 psig (3.3 MPa). Ethylene content of the reactor,in each polymerization, after reaching steady state, was maintained atthe conditions specified in Table One.

After polymerization, the reactor exit stream was introduced into aseparator where the molten polymer is separated from the unreactedcomonomer(s), unreacted ethylene, unreacted hydrogen, and diluentmixture stream. The molten polymer was subsequently strand chopped orpelletized, and, after being cooled in a water bath or pelletizer, thesolid pellets were collected. Table One describes the polymerizationconditions and the resultant polymer properties of Polymer A.

Polymer A was stabilized with 2000 ppm Irganox™ 1010 hindered phenolic,available from Ciba-Geigy.

TABLE One Polymer A Total Ethylene feed (lb/hr (kg/hr)) 2.0(0.91) FreshEthylene feed (lb/hr (kg/hr)) 2.0(0.91) Total comonomer feed (lb/hr(kg/hr)) 2.3(1.04) Fresh comonomer feed (lb/hr (kg/hr)) 2.3(1.04)Comonomer: olefin ratio (mole percent) 12.5 Hydrogen: ethylene ratio(mole percent) 0.49 Diluent ethylene ratio (weight basis) 11.1 Catalystmetal concentration (ppm) 4 Catalyst flow rate (lb/hr (kg/hr))0.32(0.14) Co-catalyst concentration (ppm) 88 Co-catalyst flow rate(lb/hr (kg/hr)) 0.46 (0.21) Aluminum concentration (ppm) 9.8 Aluminumflow rate (lb/hr (kg/hr)) 0.44(0.20) Reactor temperature (° C.) 110Ethylene concentration in reactor exit stream (weight 1.69 percent)Polymer density (g/cm³) 0.873 Polymer melt viscosity at 350° F. (177°C.) 4300 (centipoise (grams/(cm . second)) (43)

EXAMPLE ONE

The following components are heated to 180° C. in a standard mixer andare blended at low speed to avoid introducing air bubbles into the meltin the amounts indicated in Table One (A). Polymer A is a substantiallylinear ethylene/1-octene copolymer having a density of 0.873 g/cm³ and amelt viscosity of 4300 centipoise (43 grams/cm·second) at 177° C.,available from The Dow Chemical Company. The tackifier is Escorez 1102-MC₅ resin, available from Exxon Chemical Company, and having a density of0.970 g/cm³ and a viscosity of 7500 centipoise (75 grams/cm·second) at140° C. The mineral oil is Midicway 68, available from Statoil, andhaving a density of 0.870 g/cm³ and a viscosity of 71 centistokes at 40°C. The wax is Polyace 573 maleic-anhydride grafted wax, available fromAllied Signal, and having a maximum viscosity of 600 centipoise (6grams/cm·second) at 140° C., a hardness of 3 to 6 dmm at 25° C., aMettler drop point of 104 to 107° C., and no more than 0.06 percent freemaleic anhydride. TiO₂, rutile, A-11; and TiO₂, anatase R-011, areavailable from Kronos Titan A/S. Dolomite is provided as Microdol M-200,made by Micro Minerals, and is available from Norwegian Talc AS. Sand isprovided as sodium-feldspar. Glass reflecting beads are available fromSwarco Vestglas, as Class A-OV beads.

TABLE One (A) Component Amount (weight percent) Tackifier 10 Polymer A 8Mineral Oil 2.5 Wax 1 TiO₂, rutile 1.7 TiO₂, anatase 1.7 Dolomite 30.1Sand 25 Glass beads 20

EXAMPLE TWO Spray Thermoplastic Marking Compositions

The following compositions are prepared in the manner set forth abovewith respect to Example One. Polymer B, available from The Dow ChemicalCompany, is a substantially linear ethylene/1-octene copolymer having amelt viscosity at 350° F. (177° C.) of 2700 centipoise (27grams/cmsecond) and a density of 0.892 g/cm³.

The thermoplastic marking compositions are evaluated for viscosity,needle penetration, luminance factor, color, and adhesion.

Viscosity is measured using standard techniques, for instance, using aBrookfield Viscometer model DV-1+ type RVT at 200° C. with spindle No.28 at 20 rpm or a Viscotech rheometer, with viscosity measurements beingperformed at 200° C. and using a P 20 ETC spindle.

Needle penetration is measured in accordance with Test Method prEN 1871Annex J, Thermoplastic—Method for testing indentation.

Luminance factor and color coordinates are measured in accordance withTest Method prEN 1871, Annex E, Thermoplastic—Method for testingtrichromatic coordinates x, y and luminance factor β. Color coordinateswill preferably fall within the shape defined in FIG. 1.

Adhesion is measured in accordance with Test Method VVMB502:1993—Thermoplastic road marking materials, determination of atensile bond, except that the test is performed on concrete, instead ofMarshall test specimens.

The observed properties are set forth in the following Table Two:

TABLE Two Target Sample 1 Sample 2 Viscosity at 3000-5000 4350 5175 200°C. (centipoise (30-50) (43.5) (51.75) (grams/cm . second)) NeedlePenetration 5-120 34.5 62 (s/10 mm) Luminance Factor 76 ± 1 77.5 78.7Color coordinates (x/y) Figure 1 0.324/0.344 0.325/0.343 Adhesion(N/mm²) greater than 1.3 1.42 0.99

As set forth in Table Two, the formulation of Sample 1 satisfies each ofthe targeted criteria, making it a preferred relative to the formulationof Sample 2.

EXAMPLE THREE Extrusion Thermoplastic Marking Compositions

The following compositions are prepared in the manner set forth abovewith respect to Example One. Polymer B, available from The Dow ChemicalCompany, is a substantially linear ethylene/1-octene copolymer having amelt viscosity at 350° F. (177° C.) of 2700 centipoise (27grams/cm·second) and a density of 0.892 g/cm³.

The thermoplastic marking compositions are evaluated for viscosity,needle penetration, luminance-factor, color, and adhesion in accordancewith the procedures set forth with respect to Example Two.

The observed properties are set forth in the following Table Three:

TABLE Three Target Sample 1 Sample 2 Viscosity at 6000-9000 4850 6450200° C. (centipoise (60-90) (48.5) (64.5) (grams/cm . second)) NeedlePenetration 5-45 33 55 (s/10 mm) Luminance Factor 76 ± 1 78.4 78.6 Colorcoordinates (x/y) Figure 2 0.324/0.343 0.324/0.343 Adhesion (N/mm²)greater than 1.3 1.42 0.99

EXAMPLE FOUR

The following compositions are prepared in the manner set forth abovewith respect to Example One.

The polymers utilized in the binder formulations are as set forth in thefollowing Table Four, wherein each is a substantially linearethylene/1-octene copolymer, available from The Dow Chemical Company:

TABLE Four Melt viscosity at 350° F. (177° C.) (centipoise Density(g/cm³) (grams/cm . second)) Polymer A 0.873 4300 (43) Polymer B 0.8922700 (27) Polymer C (comparative) 0.870 1000* (10) Polymer D 0.880 5000(50) Polymer E (comparative) 0.880 1000* (10) Polymer F 0.890 1000 (10)*The reported values are melt indices (I₂), in units of g/10 minutes, asopposed to melt viscosities.

The thermoplastic marking compositions are evaluated for viscosity,needle penetration, luminance factor, color, and adhesion in accordancewith the procedures set forth with respect to Example Two.

The observed properties are set forth in the following Table Five:

TABLE Five Nee- Viscosity dle at 200° C. pene- Color Ad- (centipoisetration Lum- coor- hesion (grams/cm . (s/ inance dinates (N/ second)) 10mm) Factor (x/y) mm²) Target 4000-6000 5-45 76 ± 1 less (40-60) than 1.3Sample 6 5350 56 78.1 0.323/0.341 1.71 (Polymer B) (53.5) Sample 7 107700 77.8 0.324/0.343 0.83 (Comparative) (107.7) (Polymer C) Sample 8 73500 77.7 0.324/0.343 0.84 (Polymer A) (73.5) Sample 9 7275 5.5 77.60.324/0.343 0.93 (Polymer D) (727.5) Sample 10 10050 6 77.4 0.326/0.3440.88 (Comparative) (100.5) (Polymer E) Sample 11 4025 48.5 78.00.325/0.344 1.26 (Polymer F) (40.25)

EXAMPLE FIVE

In a preferred embodiment of the invention, the thermoplastic markingcomposition will satisfy the specifications set forth in the followingTable Six:

TABLE Six Product All- Spray Alt. Specifications around plastic ProfiledPlast. Viscosity at 200° C. 4000- 2000- 10000- 4000- (centipoise(grams/7000 5000 14000 9000 cm . second)) (40-70) (20-50) (100-140) (40-90)Needle penetration(s/10 mm) 5-120 5-120 >60* 5-120 Luminance Factor >75Color coordinates (x,y) diagram 1 Adhesion (N/mm²) >1,3

The formulation identified as “all-around” is designed to be suitablefor application by extrusion, screed, or spray techniques. Theformulation identified as “spray plastic” is designed to exhibitpreferred performance in spray applications. The formulation identifiedas “profiled” is designed to exhibit preferred performance in extrusionapplications. The formulation identified as “alt. plast.” is similar tothe “all-around” formulation, excepting that an alternate plasticizer isemployed.

The formulations were prepared in the manner set forth above withrespect to Example One. All testing was conducted using the measurementtechniques set forth above with respect to Example Two. The formulationsare set forth in the following Tables Seven through Ten. The datameasured on the formulations are set forth in Table Eleven.

TABLE Seven All Around Supplier Tradename Component Weight % The DowChemical Polymer A, as 8.00 Co. described above Exxon Chemical Escorez1102-RM C₅ resin 10.50 Esso (Exxon Primol 542 Paraffinic Oil 2.50Chemical) Allied Signal Polyace 573 Wax 1.00 Zaklady Chemicane TytanpolR001 Titanium dioxide 6.00 “Police” S.A. rutile (Poland) Norwegian TalcMicrodol M-200 Dolomite 1 15.00 Strabruken AB A-40 Dolomite 2 27.00Swarco Vestglas 300-800 mm Intermix glass 30.00 beads Total formulation100.00

TABLE Eight Spray Plastic Supplier Tradename Component Weight % The DowChemical Polymer A 9.50 Co. Exxon Chemical Escorez 1102-RM C₅ resin11.50 Esso (Exxon Primol 542 Paraffinic Oil 3.00 Chemical) Allied SignalPolyace 573 Wax 1 1.00 Hüls Vestowax C-80 Wax 2 1.00 Zaklady ChemicaneTytanpol R001 Titanium dioxide 5.00 “Police” S.A. rutile (Poland)Norwegian Talc Microdol M-200 Dolomite 1 10.00 Strabruken AB A-40Dolomite 2 59.00 Total formulation 100.00

TABLE Nine Extrusion for profiled lines Supplier Tradename ComponentWeight % The Dow Chemical Polymer A, as 8.00 Co. Exxon Chemical Escorez1102-RM C₅ resin 8.00 Esso (Exxon Primol 542 Paraffinic Oil 2.50Chemical) Allied Signal Polyace 573 Wax 1 0.50 Hüls Vestowax C-80 Wax 21.00 Miljstek Finsikt Glass fiber 1.00 Zaklady Chemicane Tytanpol R001Titanium dioxide 6.00 “Police” S.A. rutile (Poland) Kronos Titan Kronos1002 Titanium dioxide 3.70 anatase Norwegian Talc Microdol M-200Dolomite 1 15.00 Strabruken AB A-40 Dolomite 2 24.30 Swarco Vestglas300-800 mm Intermix glass 30.00 beads Total formulation 100.00

TABLE Ten All-Around with Alternate Plasticizer Supplier TradenameComponent Weight % The Dow Chemical Polymer A 8.50 Co. Exxon ChemicalEscorez 1102-RM C₅ resin 8.50 BP Chemicals Ltd. Hyvis 30 Polybutene 4.00Hüls Vestowax C-80 Wax 1.00 Zaklady Chemicane Tytanpol R001 Titaniumdioxide 5.00 “Police” S.A. rutile (Poland) Norwegian Talc Microdol M-200Dolomite 1 15.00 Strabruken AB A-40 Dolomite 2 28.00 Swarco Vestglas300-800 mm Intermix glass 30.00 beads Total formulation 100.00

TABLE Eleven Performance of the Thermoplastic Coating CompositionsProduct Specifications All-round Spray plastic Profiled Alt. Plast.Viscosity at 6275 4525 12400 7475 200° C. (62.75) (45.25) (124) (74.75)(centipoise (grams/ cm . second Needle 74 94 6 53 penetration (s/10 mmLuminance 84.5 83.8 80.8 78.9 Factor Colour 0.322/0.342 0.323/0.3430.324/0.343 0.324/0.343 coordinates (x,y) Adhesion 1.7 2.0 * 1.1**(N/mm²) *No results because the epoxy has not cured **The materialbroke; it did not loosen from the surface

The subject invention has been described above, and has been exemplifiedin the Examples. Various modifications within the spirit and scope ofthe invention will be apparent to one skilled in the art. Accordingly,the scope of the invention shall be limited only by the followingclaims.

What is claimed is:
 1. A thermoplastic marking composition comprising:(a) from 10 to 80 weight percent of a binder, which in turn comprises:(i) from 1 to 99 weight percent, based on binder, of at least onehomogeneous polymer produced by a single site catalyst system; (ii) from5to 70 weight percent, based on binder, of at least one tackifier; and(b) from 20 to 90 weight percent of an inorganic filler wherein thethermoplastic marking composition has a luminance factor of at least 70as measured by prEN 1871, Annex E.
 2. The thermoplastic markingcomposition of claim 1, wherein the at least one homogeneous polymer isan ethylene/α-olefin interpolymer having a density of from 0.855 to0.920 g/cm³.
 3. The thermoplastic marking composition of claim 1,wherein the at least one homogeneous polymer is an ethylene/α-olefininterpolymer having a melt viscosity at 350° F. (177° C.) of from 500 to9000 centipoise (5 to 90 grams/cm·second).
 4. The thermoplastic markingcomposition of claim 1, 2, or 3, wherein the at least one homogeneouspolymer is an interpolymer of ethylene and at least one C₃-C₂₀ α-olefin.5. The thermoplastic marking of claim 1, 2, or 3, wherein the at leastone tackifier is selected from the group consisting of rosinderivatives, rosin esters, natural and synthetic terpenes,aliphatic-based tackifiers, aromatic-based tackifiers, mixedaliphatic-aromatic petroleum based tackifiers, and mixtures thereof. 6.The thermoplastic marking composition of claim 1, 2, or 3, wherein theinorganic filler further comprises: from 0 to 60 weight percent sand,from 0 to 100 percent dolomite or talc, from 0 to 50 weight percentglass microspheres, and from 1 to 20 weight percent pigment.
 7. Thethermoplastic marking composition of any of the preceding claims, whichis characterized as having a melt viscosity at 350° F. (177° C.) of from4000 to 7000 centipoise (40 to 70 grams/cm·second), a needle penetrationof from 5 to 120 s/10 mm, a luminance factor of at least 75, and anadhesion of at least 1.3 N/mm².
 8. The thermoplastic marking compositionof any of the preceding claims, which is characterized as having a meltviscosity at 350° F. (177° C.) of from 2000 to 5000 centipoise (20 to 50grams/cm·second), a needle penetration of from 5 to 120 s/10 mm, aluminance factor of at least 75, and an adhesion of at least 1.3 N/mm².9. The thermoplastic marking composition of any of the preceding claims,which is characterized as having a melt viscosity at 350° F. (177° C.)of from 10,000 to 14,000 centipoise (100 to 140 grams/cm·second), aneedle penetration of at least 60 s/10 mm, a luminance factor of atleast 75, and an adhesion of at least 1.3 N/mm².
 10. The thermoplasticmarking composition of any of the preceding claims, which ischaracterized as having a melt viscosity at 350° F. (177° C.) of from4000 to 9000 centipoise (40 to 90 grams/cm·second), a needle penetrationof from 5 to 120 s/10 mm, a luminance factor of at least 75, and anadhesion of at least 1.3 N/mm².
 11. The thermoplastic markingcomposition of claim 1, 2, or 3, in the form of a hot melt extrusionroad marking, hot melt spray road marking, hot melt hand applied roadmarking, colored hot melt marked bicycle lane, simulation or trainingroad marking, preformed extruded traffic symbol or tape, flexible andsoft sports/playground surface marking, safety marking on a ship, or areflective traffic safety coating.
 12. The thermoplastic markingcomposition of claim 1, 2, or 3, in the form of an embossed reflectiveextruded marking.
 13. The thermoplastic marking composition of claim 1,2, or 3, wherein the binder further comprises (iii) at least 1 but lessthan 10 weight percent of a polyethylene which has pendant acidfunctionality moieties or is a non-functionalized wax.
 14. Thethermoplastic marking composition of claim 13, wherein component (iii)is a maleic anhydride grafted polyethylene, which is provided to thebinder (a) in an amount of from 1 to 8 weight percent.
 15. Thethermoplastic marking composition of claim 1, 2, or 3, wherein thebinder further comprises (iv) at least 1 but up to 20 weight percent ofa plasticizer.
 16. The thermoplastic marking of claim 15, whereincomponent (iv) is selected from the group consisting of hydrocarbonoils, polybutene, elastomers, and solid plasticizing agents having asoftening point above 60° C., and is provided in an amount of from 1 to15 weight percent.
 17. A method of marking a road, comprising: applyinga thermoplastic marking composition to a road surface, the thermoplasticmarking composition having a luminance factor of at least 70 as measuredby prEN 1871, Annex E and comprising from 10 to 80 weight percent of abinder and from 20 to 90 weight percent of an inorganic filler, whereinthe binder comprises (i) from 1 to 99 weight percent, based on binder,of at least one homogeneous polymer produced by a single site catalystsystem; and (ii) from 5 to 70 weight percent, based on binder, of atleast one tackifier.
 18. The method of claim 17, wherein the binderfurther comprises (iii) at least 1 but less than 10 weight percent of apolyethylene which has pendant acid functionality moieties or is anon-functionalized wax.
 19. The method of claim 17, wherein the binderfurther comprises (iv) at least 1 but up to 20 weight percent of aplasticizer.